Los autores reconocen una beca de la National Health and Medical Research Council de Australia (NHMRC # 1000674) para LJR Foster.

1. Preparación de la solución SURGILUX <ol><li> Preparar un 2% (v / v) de solución de ácido acético usando agua desionizada en un vaso de precipitados de vidrio limpio; utilizar una campana de flujo laminar para evitar la contaminación. </li><li> Pesar 0,02% (w / v) del cromóforo, verde de indocianina, ICG, en un tubo Eppendorf estéril; asegura que el tubo se envuelve en papel de aluminio para evitar cualquier penetración de la luz. </li><li> Utilizando una pipeta limpia, desechable, transferir aproximadamente 1 ml de la solución de ácido acético diluido al tubo para disolver el colorante, agitar suavemente y mantener envuelto en papel de aluminio. </li><li> Transferir el ICG solubilizado en el vaso de precipitados y se añade 2% (w / v) de polvo de quitosano antes de la adición de un agitador magnético estéril. </li><li> Cubrir el vaso con Parafilm luego envolver en papel de plata, antes de mezclar el contenido a aproximadamente 125 rpm durante 72 horas a temperatura ambiente en una campana de flujo laminar. </li><li> Transferir el contenido en tubos de centrífuga limpio y se centrifuga a 15.000 xg durante 15 min a 4 ° C para eliminar cualquier particulaTE materia. </li><li> Transferir cuidadosamente la solución SURGILUX verde en un vaso de precipitados de vidrio limpio, cubrir con Parafilm luego envolver en papel de plata, antes de almacenar en un refrigerador durante 12 horas para aumentar la viscosidad de la solución. </li></ol> 2. Fundición de SURGILUX Películas <ol><li> Usando una jeringa estéril, dispensar 8 ml de la solución SURGILUX fría en un recipiente limpio, de Petri de 95 mm de diámetro, y suavemente incline la placa para asegurar la cobertura completa de la solución. Variando la relación de volumen de la solución a la zona de fundición permite el control del espesor de película, véase la figura 1. </li><li> Eliminar las burbujas visibles de la solución usando la punta de una aguja estéril. Cubra el plato en papel de aluminio y coloque en el refrigerador para eliminar cualquier residuo de burbujas de tamaño micrométrico. </li><li> Después de 20 minutos retirar con cuidado la placa de Petri de la nevera, coloque en una campana de flujo laminar, cubrir con papel de aluminio y dejar que se evapore la solución durante 3 semanas. </li><li> Después de la complete evaporación, la puntuación de los bordes exteriores de la película SURGILUX verde claro en la placa de Petri y suavemente &#39;cáscara&#39; la película lejos de la superficie del plato. </li><li> La película SURGILUX debe ser flexible y fácilmente manipulado sin rasgarse o romperse. </li><li> La tienda de las películas SURGILUX circulares en la placa de Petri envueltas en papel de plata en seco hasta que esté listo para su uso. </li></ol> 3. La activación de láser SURGILUX películas adhesivas <ol><li> Para demostrar el proceso de activación del láser que se use un trozo de tejido bovino tales como carne cortada a un tamaño de 15 mm de ancho y 20 mm de longitud. Diseccionar el tejido en una línea recta usando un Número de cuchilla quirúrgica 10, para producir 2 piezas de 15 por 10 mm. </li><li> Aproximado las dos piezas de tejido de manera que sus bordes se toquen pero no se superponen, y usando un hisopo de algodón o gasa, suavemente absorber cualquier exceso de líquido. </li><li> A continuación, cortar un trozo de película SURGILUX 7 x 9 mm y coloque cuidadosamente los longitudinalmente a través de la película dividida en dos partes pIECE de tejido, luego presione suavemente con un bastoncillo de algodón seco. </li><li> Películas SURGILUX se activan usando un láser de diodo de infrarrojos en un ajuste de 120 mW. Como se trata de un láser de clase III B, las medidas de seguridad apropiadas deben ser tomadas, incluyendo el uso de gafas de seguridad apropiadas para todo el personal. </li><li> A partir de la esquina, irradiar el SURGILUX con un láser infrarrojo a 120 mW y un tamaño de punto de luz de 1 mm de diámetro. Pasar el punto del haz sobre la película de verde a un ritmo de aproximadamente 1 mm por segundo. Repetir el proceso de irradiación de dos veces más. </li></ol> 4. La fuerza de la reparación <ol><li> Cuidadosamente asegurar los extremos del tejido en las mordazas de un instrumento de ensayo de tracción. Estamos utilizando un Instron Mini55 sistema con una célula de carga de 50 Newton. La carga máxima, resistencia a la tracción, y la extensión a la rotura se calcularon utilizando software Bluehill ordenador (EE.UU.). Medios de al menos 10 muestras fue determinada (n = 10). </li><li> Tomad el &#39;slack&#39;y luego se separan las piezas de tejido a una velocidad de 1 mm por segundo, hasta que las dos piezas de tejido unidas por la tira SURGILUX separado completamente. </li></ol>

<ol>
	<li>Kjaergard, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Suture+support:+is+it+advantageous.">Suture support: is it advantageous.</a> Am. J. Surg. 182, 15S-20S (2001).</li><li>Lauto, A., Mawad, D., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesive+biomaterials+for+tissue+reconstruction.">Adhesive biomaterials for tissue reconstruction.</a> J. Chem. Tech. Biotech. 83, 464-472 (2008).</li><li>Fung, L. C., Mingin, G. C., Massicotte, M., Felsen, D., Poppas, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+temperature+on+tissue+thermal+injury+and+wound+strength+after+photochemical+wound+closure.">Effects of temperature on tissue thermal injury and wound strength after photochemical wound closure.</a> Lasers Surg. Med. 25, 285-290 (1999).</li><li>Piribo, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Glues &amp; Sealants: Industry Background Report. , (2005).</li><li>Lauto, A., Hook, J., Doran, M., Camacho, F., Poole-Warren, L. A., Avolio, A., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chitosan+adhesive+for+laser+tissue-welding:+in+vitro+characterisation.">Chitosan adhesive for laser tissue-welding: in vitro characterisation.</a> Lasers Surg. Med. 36, 193-201 (2005).</li><li>Lauto, A., Stoodley, M., Marcel, H., Avolio, A., Sarris, M., McKenzie, G., Sampson, D. D., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+and+in+vivo+tissue+repair+with+laser-activated+chitosan+adhesive.">In vitro and in vivo tissue repair with laser-activated chitosan adhesive.</a> Lasers Surg. Med. 39, 19-27 (2007).</li><li>Lauto, A., Foster, L. J. R., Avolio, A., Sampson, D., Raston, C., Sarris, M., McKenzie, G., Stoodley, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sutureless+Nerve+Repair+with+Laser-Activated+Chitosan+Adhesive:+A+Pilot+in+vivo+Study.">Sutureless Nerve Repair with Laser-Activated Chitosan Adhesive: A Pilot in vivo Study.</a> J. Photomed. Laser. Surg. 26 (3), 227-234 (2008).</li><li>Mar&#231;al, H., Badylak, S. F., Sellaro, T. L., Lauto, A., Foster, L. J. R., Mahler, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+coalescence+of+decellularized+tissue+scaffolds,+laser-activated+chitosan+bioadhesive+and+olfactory+ensheathing+cells+for+tissue+repair+and+regeneration+of+the+spinal+cord.">The coalescence of decellularized tissue scaffolds, laser-activated chitosan bioadhesive and olfactory ensheathing cells for tissue repair and regeneration of the spinal cord.</a> Lasers Med. Sci. 23 (1), 96 (2008).</li><li>Foster, L. J. R., Thomson, K., Marcal, H., Butt, J., Watson, S., Wakefield, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+chitosan-vancomycin+composite+biomaterial+as+a+laser+activated+surgical+adhesive+with+regional+antimicrobial+activity.">A chitosan-vancomycin composite biomaterial as a laser activated surgical adhesive with regional antimicrobial activity.</a> Biomacromolecules. 11 (12), 3563-3570 (2010).</li><li>Shahbazi, J., Marcal, H., Watson, S., Wakefield, D., Sarris, M., Foster, L. J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sutureless+sealing+of+penetrating+corneal+wounds+using+a+laser-activated+thin+film+adhesive.">Sutureless sealing of penetrating corneal wounds using a laser-activated thin film adhesive.</a> Lasers Surg. Med. , .</li><li>Meyers, M. A., Chen, P. -. Y., Lin, A. Y. -. M., Seki, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biological+materials:+Structure+and+mechanical+properties.">Biological materials: Structure and mechanical properties.</a> Prog. Mater. Sci. 53 (1), 1-206 (2008).</li></ol>

El quitosano puede ser obtenido en una variedad de pesos moleculares y con diferentes grados de deactylation (DDA). Las variaciones en la pureza de quitosano puede conducir a la presencia de partículas en la solución SURGILUX; centrifugación se utiliza para eliminar estos y debería resultar en una solución de color verde transparente. Sin embargo, la filtración también se puede utilizar como una etapa de fabricación adicional o alternativa. Como con cualquier tratamiento de materiales, variaciones, tales como qu...

<table border="1"><tbody><tr><td> Nombre del reactivo / equipo </td><td> Empresa </td><td> Número de catálogo </td><td> Comentarios (opcional) </td></tr><tr><td> Chitosan </td><td> Sigma-Aldrich </td><td> 448877 </td><td></td></tr><tr><td> Verde de indocianina </td><td> Sigma-Aldrich </td><td> I2633 </td><td> También conocido como Cardiogreen </td></tr><tr><td> Ácido acético </td><td> Sigma-Aldrich </td><td> 320099 </td><td></td></tr><tr><td> Infra-rojo diodo láser con fibra de entrega. (808 nm, 120 mW, núcleo del haz 200 micras) </td><td> CNI Láser </td><td> Fc-808 </td><td> Sistema variable de hasta 5 W de potencia </td></tr><tr><td> Láser gafas de seguridad </td><td> CNI Láser </td><td> LS-G </td><td></td></tr><tr><td> Aparato de ensayo de tracción </td><td> Instron Pty Ltd </td><td> 5542 </td><td> 50 N célula de carga </td></tr></tbody></table>

a chitosan based, laser activated thin film surgical adhesive, 'surgilux': preparation and demonstration

Las suturas son una tecnología de 4.000 años de edad que siguen siendo el &quot;patrón oro&quot; para cierre de heridas en virtud de su fuerza de reparación (~ 100 KPa). Sin embargo, las suturas pueden actuar como un nido para la infección y en muchos procedimientos son incapaces de efectuar la reparación de heridas o interferir con la regeneración del tejido funcional. 1 pegamentos y adhesivos quirúrgicos, tales como los basados ​​en fibrina y cianoacrilatos, se han desarrollado como alternativas a las suturas para la la reparación de tales heridas. Sin embargo, los actuales adhesivos comerciales también tienen desventajas significativas, que van desde la transferencia viral y priones y la falta de fuerza de reparación como con las colas de fibrina, a toxicidad del tejido y la falta de biocompatibilidad para los adhesivos a base de cianoacrilato. Además, los adhesivos quirúrgicos disponibles actualmente tienden a ser a base de gel y se puede haber extendido los tiempos de curado que limitan su aplicación. 2 Del mismo modo, el uso de láseres UV para facilitar la reticulación mecanismos a base de proteínas o albúmina &#39;solDers &quot;puede conducir a daños en el ADN durante la soldadura láser del tejido (LTW) predispone a daño térmico a los tejidos. 3 A pesar de sus desventajas, adhesivos y LTW han capturado aproximadamente el 30% del mercado de cierre de la herida informado de que más de 5 dólares EE.UU. millones de dólares al año, un testimonio significativo a la necesidad de una tecnología sin sutura. 4 En la búsqueda de la tecnología de sutura hemos utilizado quitosán como un biomaterial para el desarrollo de una película flexible, delgada, láser adhesivo activado quirúrgico denominado «SURGILUX &#39;. Este bioadhesivo novela utiliza una combinación única de los biomateriales y la fotónica que están aprobados por la FDA y utilizado con éxito en una variedad de aplicaciones biomédicas y productos. SURGILUX supera todas las desventajas asociadas con suturas y adhesivos quirúrgicos actuales (ver Tabla 1). En esta presentación se presenta el protocolo relativamente sencillo para la fabricación de SURGILUX y demostrarsu activación láser y resistencia de la soldadura del tejido. Películas SURGILUX adherirse a tejido de colágeno sin modificación química tal como la reticulación y mediante irradiación utilizando una comparativamente baja potencia (120 mW) láser de infrarrojos en lugar de luz UV. Películas de quitosano tienen una atracción adhesivo natural pero débil al colágeno (~ 3 KPa), activación por láser de la base de quitosano SURGILUX películas acentúa la fuerza de esta adhesión a través de interacciones de cadena de polímero como consecuencia de la expansión térmica transitoria. 5 Sin esta &quot;activación&quot; proceso , películas SURGILUX se eliminan fácilmente. 6-9 SURGILUX se ha probado tanto in vitro como in vivo en una variedad de tejidos incluyendo los nervios, el intestino, la duramadre y la córnea. En todos los casos se demostró una buena biocompatibilidad y daño térmico insignificante como consecuencia de la irradiación. 6-10

Centrifugación lleva a una solución transparente verde, lo que aumenta la viscosidad después del almacenamiento a 4-6 ° C. Después de reposar durante 3 semanas, la solución de color verde se convierte en una película transparente verde SURGILUX aproximadamente 20 micras de espesor y, como se demuestra en el vídeo, es fácilmente flexible. Tras la irradiación con el láser, los lazos de película SURGILUX al tejido. Esto se puede observar en los bordes de la película donde el tejido...

Watch this Scientific Journal Video about A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, 'SurgiLux': Preparation and Demonstration at JoVE.com

A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, &#039;SurgiLux&#039;: Preparation and Demonstration

La fabricación de una novela, de película delgada adhesivo flexible quirúrgico de los ingredientes aprobados por la FDA, el quitosano y verde de indocianina se describe. La unión de este adhesivo para tejido colágeno a través de un proceso de activación simple con una baja potencia de infrarrojos láser se demuestra.

A Based Chitosan, Laser adhesivo activado Thin Film quirúrgica, &#39;SURGILUX&#39; Preparación y Demostración

Sutures are a 4,000 year old technology that remain the 'gold-standard' for wound closure by virtue of their repair strength (~100 KPa). However, sutures ...

a-chitosan-based-laser-activated-thin-film-surgical-adhesive-surgilux

Research

JoVE Journal

Bioengineering

A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, 'SurgiLux': Preparation and Demonstration

13.1K vistas.  University of New South Wales. La fabricación de una novela, de película delgada adhesivo flexible quirúrgico de los ingredientes aprobados por la FDA, el quitosano y verde de indocianina se describe. La unión de este adhesivo para tejido colágeno a través de un proceso de activación simple con una baja potencia de infrarrojos láser se demuestra.

Video: A Chitosan Based, Laser Activated Thin Film Surgical Adhesive, 'SurgiLux': Preparation and Demonstration

Constructing a Collagen Hydrogel for the Delivery of Stem Cell-loaded Chitosan Microspheres

Multipotent stem cells have been shown to be extremely useful in the field of regenerative medicine1-3. However, in order to use these cells effectively for tissue regeneration, a number of variables must be taken into account. These variables include: the total volume and surface area of the implantation site, the mechanical properties of the tissue and the tissue microenvironment, which includes the amount of vascularization and the components of the extracellular matrix. Therefore, the materials being used to deliver these cells must be biocompatible with a defined chemical composition while maintaining a mechanical strength that mimics the host tissue. These materials must also be permeable to oxygen and nutrients to provide a favorable microenvironment for cells to attach and proliferate. Chitosan, a cationic polysaccharide with excellent biocompatibility, can be easily chemically modified and has a high affinity to bind with in vivo macromolecules4-5. Chitosan mimics the glycosaminoglycan portion of the extracellular matrix, enabling it to function as a substrate for cell adhesion, migration and proliferation. In this study we utilize chitosan in the form of microspheres to deliver adipose-derived stem cells (ASC) into a collagen based three-dimensional scaffold6. An ideal cell-to-microsphere ratio was determined with respect to incubation time and cell density to achieve maximum number of cells that could be loaded. Once ASC are seeded onto the chitosan microspheres (CSM), they are embedded in a collagen scaffold and can be maintained in culture for extended periods. In summary, this study provides a method to precisely deliver stem cells within a three dimensional biomaterial scaffold.

A major hurdle in current stem cell therapies is determining the most effective method to deliver these cells to host tissues. Here, we describe a chitosan-based delivery method that is efficient and simple in approach, while allowing adipose-derived stem cells to maintain their multipotency.

La construcción de un hidrogel de colágeno para la entrega de la madre microesferas cargadas con células quitosano

Multipotent stem cells have been shown to be extremely useful in the field of regenerative medicine1-3. However, in order to use these cells effectively ...

Investigación

Bioingeniería

Fabrication and Application of Rose Bengal-chitosan Films in Laser Tissue Repair

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two tissue edges1,2. These are then irradiated by a laser that is selectively absorbed by the RB. The resulting photochemical reactions supposedly crosslink the collagen fibers in the tissue with minimal heat production3. In this report, RB has been incorporated in thin chitosan films to fabricate a novel tissue adhesive that is laser-activated. Adhesive films, based on chitosan and containing ~0.1 wt% RB, are fabricated and bonded to calf intestine and rat tibial nerves by a solid state laser (&lambda;=532 nm, Fluence~110 J/cm2, spot size~0.5 cm). A single-column tensiometer, interfaced with a personal computer, is used to test the bonding strength. The RB-chitosan adhesive bonds firmly to the intestine with a strength of 15 &plusmn; 6 kPa, (n=30). The adhesion strength drops to 2 &plusmn; 2 kPa (n=30) when the laser is not applied to the adhesive. The anastomosis of tibial nerves can be also completed without the use of sutures. A novel chitosan adhesive has been fabricated that bonds photochemically to tissue and does not require sutures.

Sutures are usually needed to repair tissue during surgical procedures. However, their application can be problematic as they are invasive and may damage tissue. The fabrication and application methods of a novel tissue adhesive are here reported. This adhesive film is laser-activated and does not require the use of sutures.

Fabricación y Aplicación de Rosa de Bengala-quitosano Films en Tissue Repair Laser

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two ...

Creating Adhesive and Soluble Gradients for Imaging Cell Migration with Fluorescence Microscopy

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as growth factors. Here, we outline a method to create opposing gradients of adhesive and soluble cues in a microfluidic chamber, which is compatible with live cell imaging. A copolymer of poly-L-lysine and polyethylene glycol (PLL-PEG) is employed to passivate glass coverslips and prevent non-specific adsorption of biomolecules and cells. Next, microcontact printing or dip pen lithography are used to create tracks of streptavidin on the passivated surfaces to serve as anchoring points for the biotinylated peptide arginine-glycine-aspartic acid (RGD) as the adhesive cue. A microfluidic device is placed onto the modified surface and used to create the gradient of adhesive cues (100% RGD to 0% RGD) on the streptavidin tracks. Finally, the same microfluidic device is used to create a gradient of a chemoattractant such as fetal bovine serum (FBS), as the soluble cue in the opposite direction of the gradient of adhesive cues.

A method for the assembly of adhesive and soluble gradients in a microscopy chamber for live cell migration studies is described. The engineered environment combines antifouling surfaces and adhesive tracks with solution gradients and therefore allows one to determine the relative importance of guidance cues.

Creación de degradados adhesivas y soluble para la migración celular con imágenes de microscopía de fluorescencia

Cells can sense and migrate towards higher concentrations of adhesive cues such as the glycoproteins of the extracellular matrix and soluble cues such as ...

Insertion of Flexible Neural Probes Using Rigid Stiffeners Attached with Biodissolvable Adhesive

Microelectrode arrays for neural interface devices that are made of biocompatible thin-film polymer are expected to have extended functional lifetime because the flexible material may minimize adverse tissue response caused by micromotion. However, their flexibility prevents them from being accurately inserted into neural tissue. This article demonstrates a method to temporarily attach a flexible microelectrode probe to a rigid stiffener using biodissolvable polyethylene glycol (PEG) to facilitate precise, surgical insertion of the probe. A unique stiffener design allows for uniform distribution of the PEG adhesive along the length of the probe. Flip-chip bonding, a common tool used in microelectronics packaging, enables accurate and repeatable alignment and attachment of the probe to the stiffener. The probe and stiffener are surgically implanted together, then the PEG is allowed to dissolve so that the stiffener can be extracted leaving the probe in place. Finally, an in vitro test method is used to evaluate stiffener extraction in an agarose gel model of brain tissue. This approach to implantation has proven particularly advantageous for longer flexible probes (&gt;3 mm). It also provides a feasible method to implant dual-sided flexible probes. To date, the technique has been used to obtain various in vivo recording data from the rat cortex.

Insertion of flexible neural microelectrode probes is enabled by attaching probes to rigid stiffeners with polyethylene glycol (PEG). A unique assembly process ensures uniform and repeatable attachment. After insertion into tissue, the PEG dissolves and the stiffener is extracted. An in vitro test method evaluates the technique in agarose gel.

La inserción de sondas Flexible Neural Usando refuerzos rígidos adjuntos con Biodissolvable Adhesivo

Microelectrode  arrays for neural interface devices that are made of biocompatible thin-film  polymer are expected to have extended functional lifetime ...

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or erosion. Amelogenin has been proven to be a critical protein for controlling the organized growth of apatite crystals. In this paper, we present a detailed protocol for superficial enamel reconstruction by using a novel amelogenin-chitosan hydrogel. Compared to other conventional treatments, such as topical fluoride and mouthwash, this method not only has the potential to prevent the development of dental caries but also promotes significant and durable enamel restoration. The organized enamel-like microstructure regulated by amelogenin assemblies can significantly improve the mechanical properties of etched enamel, while the dense enamel-restoration interface formed by an in situ regrowth of apatite crystals can improve the effectiveness and durability of restorations. Furthermore, chitosan hydrogel is easy to use and can suppress bacterial infection, which is the major risk factor for the occurrence of dental caries. Therefore, this biocompatible and biodegradable amelogenin-chitosan hydrogel shows promise as a biomaterial for the prevention, restoration, and treatment of defective enamel.

Development of Amelogenin-chitosan Hydrogel for In Vitro Enamel Regrowth with a Dense Interface

In this article, we describe a protocol for fabricating an amelogenin-chitosan hydrogel for superficial enamel reconstruction. Organized in situ growth of apatite crystals in the hydrogel formed a dense enamel-restoration interface, which will improve the effectiveness and durability of restorations.

Desarrollo de amelogenina-quitosano hidrogel para<em&gt; In Vitro</em&gt; Esmalte Recrecimiento con una interfaz Dense

Biomimetic enamel reconstruction is a significant topic in material science and dentistry as a novel approach for the treatment of dental caries or ...

Custom-designed Laser-based Heating Apparatus for Triggered Release of Cisplatin from Thermosensitive Liposomes with Magnetic Resonance Image Guidance

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect resulting in significant reductions in systemic toxicity. Nonetheless, insufficient release of encapsulated drug from liposomes has limited their clinical efficacy. Temperature-sensitive liposomes have been engineered to provide site-specific release of drug in order to overcome the problem of limited tumor drug bioavailability. Our lab has designed and developed a heat-activated thermosensitive liposome formulation of cisplatin (CDDP), known as HTLC, to provide triggered release of CDDP at solid tumors. Heat-activated delivery in vivo was achieved in murine models using a custom-built laser-based heating apparatus that provides a conformal heating pattern at the tumor site as confirmed by MR thermometry (MRT). A fiber optic temperature monitoring device was used to measure the temperature in real-time during the entire heating period with online adjustment of heat delivery by alternating the laser power. Drug delivery was optimized under magnetic resonance (MR) image guidance by co-encapsulation of an MR contrast agent (i.e.,&#160;gadoteridol) along with CDDP into the thermosensitive liposomes as a means to validate the heating protocol and to assess tumor accumulation. The heating protocol consisted of a preheating period of 5 min prior to administration of HTLC and 20 min heating post-injection. This heating protocol resulted in effective release of the encapsulated agents with the highest MR signal change observed in the heated tumor in comparison to the unheated tumor and muscle. This study demonstrated the successful application of the laser-based heating apparatus for preclinical thermosensitive liposome development and the importance of MR-guided validation of the heating protocol for optimization of drug delivery.

AN MRI-compatible&#160;custom-designed laser-based heating apparatus has been developed to provide local heating of subcutaneous tumors in order to activate release of agents from thermosensitive liposomes specifically at the tumor region.

Diseño personalizado basado en láser máquinas de calentamiento para lanzamiento disparada de cisplatino de termosensible liposomas con Resonancia Magnética Orientación Imagen

Liposomes have been employed as drug delivery systems to target solid tumors through exploitation of the enhanced permeability and retention (EPR) effect ...

Automated Lipid Bilayer Membrane Formation Using a Polydimethylsiloxane Thin Film

An artificial lipid bilayer, or black lipid membrane (BLM), is a powerful tool for studying ion channels and protein interactions, as well as for biosensor applications. However, conventional BLM formation techniques have several drawbacks and they often require specific expertise and laborious processes. In particular, conventional BLMs suffer from low formation success rates and inconsistent membrane formation time. Here, we demonstrate a storable and transportable BLM formation system with controlled thinning-out time and enhanced BLM formation rate by replacing conventionally used films (polytetrafluoroethylene, polyoxymethylene, polystyrene) to polydimethylsiloxane (PDMS). In this experiment, a porous-structured polymer such as PDMS thin film is used. In addition, as opposed to conventionally used solvents with low viscosity, the use of squalene permitted a controlled thinning-out time via slow solvent absorption by PDMS, prolonging membrane lifetime. In addition, by using a mixture of squalene and hexadecane, the freezing point of the lipid solution was increased (~16 &#176;C), in addition, membrane precursors were produced that can be indefinitely stored and readily transported. These membrane precursors have reduced BLM formation time of &#60; 1 hr and achieved a BLM formation rate of ~80%. Moreover, ion channel experiments with gramicidin A demonstrated the feasibility of the membrane system.

We demonstrate a storable, transportable lipid bilayer formation system. A lipid bilayer membrane can be formed within 1 hr with over 80% success rate when a frozen membrane precursor is brought to ambient temperature. This system will reduce laborious processes and expertise associated with ion channels.

Formación Automated bicapa lipídica membrana utilizando un polidimetilsiloxano Thin Film

An artificial lipid bilayer, or black lipid membrane (BLM), is a powerful tool for studying ion channels and protein interactions, as well as for ...

Image-guided, Laser-based Fabrication of Vascular-derived Microfluidic Networks

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic networks embedded in PEGDA hydrogels. Here, we describe the creation of virtual masks that allow for image-guided laser control; the photopolymerization of a micromolded PEGDA hydrogel, suitable for microfluidic network fabrication and pressure head-driven flow; the setup and use of a commercially available laser scanning confocal microscope paired with a femtosecond pulsed Ti:S laser to induce hydrogel degradation; and the imaging of fabricated microfluidic networks using fluorescent species and confocal microscopy. Much of the protocol is focused on the proper setup and implementation of the microscope software and microscope macro, as these are crucial steps in using a commercial microscope for microfluidic fabrication purposes that contain a number of intricacies. The image-guided component of this technique allows for the implementation of 3D image stacks or user-generated 3D models, thereby allowing for creative microfluidic design and for the fabrication of complex microfluidic systems of virtually any configuration. With an expected impact in tissue engineering, the methods outlined in this protocol could aid in the fabrication of advanced biomimetic microtissue constructs for organ- and human-on-a-chip devices. By mimicking the complex architecture, tortuosity, size, and density of in vivo vasculature, essential biological transport processes can be replicated in these constructs, leading to more accurate in vitro modeling of drug pharmacokinetics and disease.

This protocol outlines the implementation of image-guided, laser-based hydrogel degradation to fabricate vascular-derived, biomimetic microfluidic networks embedded in poly(ethylene glycol) diacrylate (PEGDA) hydrogels. These biomimetic microfluidic systems may be useful for tissue engineering applications, generation of in vitro disease models, and fabrication of advanced "on-a-chip" devices.

Guiada por imagen, fabricación basada en láser de Redes de microfluidos derivados-vascular

This detailed protocol outlines the implementation of image-guided, laser-based hydrogel degradation for the fabrication of vascular-derived microfluidic ...

Dry Film Photoresist-based Electrochemical Microfluidic Biosensor Platform: Device Fabrication, On-chip Assay Preparation, and System Operation

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An easy-to-use and low-cost sensor platform is highly desired to measure various types of analytes (e.g., biomarkers, hormones, and drugs) quantitatively and specifically. For this reason, dry film photoresist technology - enabling cheap, facile, and high-throughput fabrication - was used to manufacture the microfluidic biosensor presented here. Depending on the bioassay used afterwards, the versatile platform is capable of detecting various types of biomolecules. For the fabrication of the device, platinum electrodes are structured on a flexible polyimide (PI) foil in the only clean-room process step. The PI foil serves as a substrate for the electrodes, which are insulated with an epoxy-based photoresist. The microfluidic channel is subsequently generated by the development and lamination of dry film photoresist (DFR) foils onto the PI wafer. By using a hydrophobic stopping barrier in the channel, the channel is separated into two specific areas: an immobilization section for the enzyme-linked assay and an electrochemical measurement cell for the amperometric signal readout.
The on-chip bioassay immobilization is performed by the adsorption of the biomolecules to the channel surface. The glucose oxidase enzyme is used as a transducer for electrochemical signal generation. In the presence of the substrate, glucose, hydrogen peroxide is produced, which is detected at the platinum working electrode. The stop-flow technique is applied to obtain signal amplification along with rapid detection. Different biomolecules can quantitatively be measured by means of the introduced microfluidic system, giving an indication of different types of diseases, or, in regard to therapeutic drug monitoring, facilitating a personalized therapy.

A microfluidic biosensor platform was designed and fabricated using low-cost dry film photoresist technology for the rapid and sensitive quantification of various analytes. This single-use system allows for the electrochemical readout of on-chip-immobilized enzyme-linked assays by means of the stop-flow technique.

Seca de la película basada en la fotoresistencia el Biosensor electroquímico de microfluidos plataforma: Fabricación de dispositivo, preparación del análisis de la en-viruta y el funcionamiento del sistema

In recent years, biomarker diagnostics became an indispensable tool for the diagnosis of human disease, especially for the point-of-care diagnostics. An ...

Rat Model of Adhesive Capsulitis of the Shoulder

This proposal aims to create an in vivo rat model of adhesive capsulitis for researching potential treatment options for this condition and other etiologies of comparable arthrofibrosis. The model includes extra-articular fixation of the shoulder in rats via scapular to humeral suturing, resulting in a secondary contracture without invading the intra-articular space and resulting in decreased rotational ROM and increased joint stiffness.
We used 10 Sprague-Dawley rats for the purpose of this study. Baseline ROM measurements were taken before glenohumeral immobilization. The rats were subjected to 8 weeks of immobilization before the fixation sutures were removed and changes in ROM and joint stiffness were evaluated. To evaluate whether immobilization resulted in a significant reduction in ROM, changes in kinematics were calculated. ROM was measured at each time point in the follow-up period and was compared to the baseline internal and external ROM measurements. In order to evaluate the stiffness, joint kinetics were calculated by determining the differences in torque (text and tint ) needed to reach the initial external rotation of 60&#176; and initial internal rotation of 80&#176;.
After the removal of the extra-articular suture fixation on follow-up day 0, we found a 63% decrease in total ROM compared to baseline. We observed continuous improvement until week 5 of follow-up, with the progress slowing down around a 19% restriction. On week 8 of follow-up, there was still an 18% restriction of ROM. Additionally, on follow-up day 0, we found the torque increased by 13.3 Nmm when compared to baseline. On week 8, the total torque was measured to be 1.4 &#177; 0.2 Nmm higher than initial measurements. This work introduces a rat model of shoulder adhesive capsulitis with lasting reduced ROM and increased stiffness.

This protocol presents an in vivo rat model of adhesive capsulitis. The model includes an internal fixation of the glenohumeral joint with extra-articular suture fixation for an extended time, resulting in a decreased rotational range of motion (ROM) and increased joint stiffness.